


What Has To Be

by keirieski17



Category: The Dark Artifices Series - Cassandra Clare, The Shadowhunter Chronicles - Cassandra Clare
Genre: Anal Sex, Blow Jobs, Cunnilingus, Established Relationship, F/M, Light Dom/sub, M/M, Multi, Oral Sex, Plot What Plot/Porn Without Plot, Porn with Feelings, Threesome - F/M/M, Vaginal Sex, minor qoaad spoilers, post qoaad
Language: English
Status: Completed
Published: 2019-01-08
Updated: 2019-01-08
Packaged: 2019-10-06 13:21:03
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,781
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17345963
Author URL: https://archiveofourown.org/users/keirieski17/pseuds/keirieski17
Summary: After a few weeks apart, Mark and Cristina come to visit Kieran in the cottage. While waiting for Kieran, Cristina has a sexy dream and wakes up to find both her boys rearing to go.





	What Has To Be

**Author's Note:**

> I just loved this relationship so much, I had to write it! It does take place after QoAaD, so there are some slight spoilers if you haven't finished it. Sorry if the Spanish is flawed. I'm relatively fluent, but my grammar or word choice might be off. Constructive criticism welcome!

Cristina walked the short path up from where the Eternidad had landed Mark and her to the cottage. Flowers bloomed around the stones, neatly kept by pixies to make sure the home always felt welcoming, even after its inhabitants had been gone a while. She glanced at Mark behind her; his hair was ruffled from the cold winds in New York. It was nearing winter in the mortal world, but in Faerie it still felt like spring. The sweater Cristina wore was too warm, now.

The door had been enchanted to only open when one of the three touched it. There was no handle or doorknob—it simply swung open as if inviting them inside. Cristina breathed deeply. The house smelled like Kieran, all wind and water, and like Mark’s scent of shampoo and sweat. It was familiar and comforting to her, like a piece of her which had been missing had settled back into her heart. Living with Mark had been wonderful, but off-kilter. Kieran was a necessary part of their relationship, the missing pieces of their jigsaw puzzle.

She plopped down on the couch, content to wait for Kieran to arrive. It was the only piece of furniture in the small living room, a gift from her mother. There was a bedroom to her right and a bathroom to her left. Mark sat down beside her, leaned his head on her shoulder, and breathed a sigh of content.

“I’ve missed him,” he said.

Cristina nodded in agreement. “How long do you think it will take him to get here?” She hoped she didn’t sound like she was more excited to be with Kieran than just Mark. There was rarely jealousy between them, but Cristina still worried. They had each visited Kieran alone before, when the other was tied up in plans and duties, and it had yet to spark resentment.

“It is hard to know,” Mark said with a shrug. “Windspear travels quickly, but Faerie is a vast land.” He smiled slightly. “And Winter has been quite the annoyance for him lately.”

Cristina stifled a giggle. It was always sort of amusing to think of Winter prodding at Kieran, trying to keep the new Unseelie King proper. Then again, it was why he had been unable to get away the last time the pair tried to visit.

The two Shadowhunters tried to come at least once a week, though even that standard was often left unmet. Cristina and Mark had gone upwards of a month without Kieran, because of normal Shadowhunter duties or work with the Alliance. Kieran was often busy being, well, King and Winter was constantly breathing down his neck. Cristina was unsure of how much the general knew of Kieran’s activities in the borderlands but was sure he disapproved. As it was, it had been nearly three weeks since their schedules had aligned, but at the very least they had carved out two days this time. Sometimes visits lasted only hours.

Cristina laid her head in Mark’s lap, his hands trailing through her hair as he hummed a song he had learned in his time with the Hunt. The sound was soothing, and soon Cristina’s eyes fell shut. She trusted her boys to wake her when Kieran arrived.

***

Mark did not mind that Cristina had fallen asleep. It had been a long few weeks for them, and there was peace to be found in the cottage that didn’t exist in their world. At home, they spent their time helping refugees from Brocelind or keeping the peace between the new Clave and Downworlders, many of whom were now suspicious of the Shadowhunter government. Seelie Faeries were especially suspicious of Mark and Cristina’s relationship with the Unseelie King, which made it harder for them to work to repair damages from the Cold Peace. Their trips to Faerie, short as they may be, were much-needed reprieves from the endless nature of their work.

And besides, his Lady of Roses was beautiful as she slept. Her hair tumbled off his lap in waves, dark eyelashes stark against her brown skin. Her chest rose and fell steadily. Cristina was wearing nicer clothes than she usually did at home, but Mark didn’t mind. He understood the urge to dress up for Kieran. When there was so much time between visits, it felt like every time needed to be special.

Cristina was muttering in her sleep: “Que guapo.” Mark had learned enough Spanish when Cristina slipped out of English to understand the word for handsome. “Mark.” She moaned his name in a way that made Mark wonder what she was dreaming about. Whatever it was, he was glad to know he featured. “Quiero tocarte, mi hada amor,” she whined. “Por favor.”

Mark smiled. He had to admit: their sex life had been slightly lacking. Most nights, they were too tired to do much besides cuddle up together and watch a movie. Considering that and their current location, he supposed such dreams weren’t surprising. He almost reached out to touch her and let Kier walk into a pleasant surprise but heard hooves near the cottage before he could move. Cristina didn’t stir. She continued to murmur in Spanish, and Mark grinned in anticipation as the door opened. Kieran wore a similar grin, his hair a bright aquamarine, and opened his mouth to speak before Mark put a finger to his lips and gestured to the sleeping woman in his lap.

“Listen,” he whispered. His smile had turned wicked.

Kieran sat on the other side of the couch, gently lifting Cristina’s legs and putting them in his lap. He leaned over to kiss Mark hello, pausing as she moaned again. Kieran cocked his head.

“Is she…?”

Mark chuckled quietly. “She’s dreaming, Kier.” Cristina groaned both their names in succession.

“She dreams of us?” Kieran asked, genuine surprise in his voice.

When Mark next spoke, his tone was more sincere. “She’s missed you. _We’ve_ missed you.”

Kieran smiled, and then chuckled. Holding Mark’s face in his hand, he asked, “Have you not been keeping our lady satisfied, my Mark? Must she dream to seek pleasure?”

Mark sighed. “The weeks since we last saw you have been long.”

“For me as well.” Kieran’s hair darkened as his mood shifted. “Being King is not a pleasant affair, and there is no one to warm my bed at night.”

Mark placed a hand on his shoulder, only slightly relieved to hear the position of Consort remained unfilled. “I’m sorry a King is what you must be. But here, with us, you are free.”

Kier smiled, still a little sad. “You speak the truth. Although, I feel that if we do not wake Cristina soon, she will be quite displeased with us.”

Mark nodded, knowing Cristina would be upset if she missed time with Kieran. He went to wake her, but Kieran shook his head.

“Please, let me.”

***

Kieran had ridden Windspear as fast as he could go to reach the cottage, knowing he was running late. His two loves, his partners in life, would be waiting for him still, and they had precious little time. He had wanted to hear their voices, to touch them and lose his regrets in their kisses. Now, in front of him, his Cristina rested on Mark’s lap, so beautiful. He leaned over gently. The angle was awkward, and he was only just able to accomplish what he wanted. Their lips pressed together, and Cristina kissed him back before she even opened her eyes. A little dazed, she pulled away from him slightly and smiled.

“Kier! I was just dreaming of you,” she said, voice still a little raspy from sleep.

Mark laughed, planting a kiss on her forehead. “We know.”

“Huh? You…” she groaned and sat up, sliding into the space between the two men. “By the Angel, was I talking in my sleep?”

Kieran let his hand trail across her face with the gentle familiarity than came from a year of love and companionship. “More than that, my Princess. Why don’t you tell Mark and I the kind of dream you were having?”

Cristina’s tan skin turned pink in embarrassment, and Kieran thought that he had never loved her more. Then again, he said that every time he saw her.

“I don’t know what you’re talking about,” she said, almost petulantly.

Kieran grabbed her chin, gently but firmly. “You shouldn’t lie to a King, my love.”

Mark pulled her onto his lap and slid them closer to Kieran. “Especially one who can’t lie to you,” he chuckled before planting a kiss on her neck. “That’s hardly fair.”

Cristina leaned back into Mark and put her hand over Kieran’s. “I dreamed of the first time we were here together, when the house was empty except for us.”

Kieran knew exactly the day she spoke of. “We lay on the floor, the three of us, and I took you into my lap.” He clearly remembered it, all of them naked, desperate for contact.

Cristina nodded. “Everything was still so new for us, then.”

Kieran laughed. “Ah, but I may have forgotten what happened next. Perhaps I need you to jog my memory, as mortals say.” The perhaps was the only reason he had been able to speak those words. He knew he would never forget the sight of her skin, exposed to him, any more than he could forget any other time he had spent with her or Mark. He remembered with clarity the first time Mark had come to him in the Hunt, desperate to feel loved.  

Mark nuzzled her, seeming to like the direction this conversation was turning. “Indeed, Cristina, my memory on the subject is poor.”

She smiled, almost in spite of herself, and leaned back into Mark. “You’re both dirty liars, and you know it.”

Mark reached up to open the top button of her dress. “Yet, my love, you have not said you would deny us the reminder.” He popped another button.

Kieran’s hair was growing dark again, but with desire rather than sorrow. “What was she saying in her sleep, Mark?”

Another button. “Quiero tocarte,” Mark repeated in what even Kieran knew was poor Spanish. When Cristina spoke her native tongue it sounded like music. When Mark tried, he sounded like a Kelpie. But Kieran loved listening to him try, all the same. It was endearing.

Like Mark, Kieran had picked up certain Spanish phrases. “I want to touch you,” he translated. His leather trousers weren’t doing much to hide his arousal.

“Mi hada amor,” Cristina said.

“You said that too,” Mark pointed out, the last few buttons all coming undone, then looked at Kieran. “It seems she was longing to touch you, “Faerie love,’” There was nothing in Mark’s voice except desire and gentle teasing.

“You have my permission, then. Now and always.”

***

Cristina stopped pretending she hadn’t been dreaming of their bodies pressed together, of the parts of them that belonged only to each other. She reached out a hand behind Kieran’s neck and pulled him in to her.

Every kiss with Kieran had the power to bring Cristina to her knees, and this one was no different. His tongue ran over her lips, his teeth nibbling and sucking. Mark’s hands trailed down her body, to the hem of her dress, and pulled it over her head. Cristina wore a plain black bra and panties, but by the way Kieran looked at her one would have thought it was the sexiest thing he had ever seen. His hands found a place against her now bare waist as Mark began to kiss her neck, gently. Cristina liked her private life to stay private, so any love bites were kept out of sight.

“Kier,” she moaned as he pulled away from her.

He stood and lifted her from Mark’s lap. Her legs wrapped around his waist and he carried her to the bedroom, Mark trailing behind. In an instant, she was tossed on the bed and Kieran laid on top of her. Mark had other plans, though, and rolled Kieran onto his back. Before Kieran could voice objection or approval, Mark was on top of him, lips crashing into his. Cristina noticed he was bare from the hips up, his shirt lost somewhere between the living room and the bed. Not one to be taken control of, Kieran sat up, lips never breaking contact. He began to undo his velvet doublet. Normally he would have worn a simpler outfit to see them, but it seemed that he had been in a rush today. He pushed it off him and his dress shirt after that. Cristina crawled behind him and ran her nails down his back in the way he liked and he hissed.

“How did I end up in the middle?” he asked once he had broken away from Mark, chest heaving.

Mark nipped his ear. “You’re not always in charge, Kier.”

Pressing a kiss to his shoulder, Cristina said, “We want to make you feel good, Kieran.”

Kieran reached behind her, undoing the clasp on her bra. Women in Faerie didn’t wear them; it had taken him ages to be able to get it off as quickly as he did now. There was a time when Cristina would have felt shy to be so exposed, but not now. Not with them.

“It seems unfair that I’m the least clothed,” she pouted. She had never pictured herself as a tease, but it was the role that had come naturally to her. Besides, it turned Kieran on.

Kieran undid the button on Mark’s jeans, pulling them down with his boxers. Mark quickly kicked them off, finally revealing every beautiful inch of skin. He took Cristina’s breath away as much as he ever had.

Cristina wasted no time going over to him and wrapping her hands around his cock. She stroked it, enough for him to groan but nowhere near firm enough for him to come anywhere close to orgasm. Her tongue ran over Mark’s nipple, feeling it harden in her mouth. For a few moments, it seemed Kieran was content simply to watch the two people he loved touch each other. But that did not last long, and soon his hands were cupping Cristina’s breasts, causing her to moan. Without any conscious thought, she ground her hips backwards, his cock responding to her touch. His nimble fingers made quick work of the ties on his pants and soon he was bare too. He pulled Cristina onto her back and dragged her panties off of her with his teeth.

***

“Don’t move,” Kieran ordered. He loved the sight of her, wanting him— _needing_ him.

“Kier,” she whined and he pinned her hands over her head. He leaned down until his mouth was nearly touching her ear.

“Obey your King, my Lady.” There was a warning in his voice. She nodded vigorously. Kieran had so loathed the title of King he would never have thought to use it with Mark and Cristina. But she had called him King first, the word slipping out of her mouth in a moment of ecstasy. Nothing had ever made him harder. Content that she would do as she was told, as she always did, he turned his attention to the blonde boy in front of him. “Come here, Mark.”

Mark sat on his lap, straddling him. His eyes, one Blackthorn blue and one gold, bore into his, the same need in his eyes as he had seen in Cristina’s. As he knew they could see in his own. Kieran reached between them, feeling for Mark’s cock. He moaned when he found it, resting his head on Mark’s chest. “You’re so hard, my love.” He stroked slowly, his hand rubbing against his own cock as he did.

Mark moaned his name: “Kieran.” There wasn’t a more beautiful sound in the world.

“Touch me.” Kieran’s words were somewhere between a command and a plea, and Mark was happy to oblige. His hands were on Kieran’s face, on his hips, in his hair as he kissed him. Then he slid to the floor, gesturing for the Faerie to stand. For once, Kieran was happy to obey.

He nearly screamed once Mark’s lips were around his cock. He thought briefly about how, while Mark and Cristina had each other to satisfy their wanton urges, he was alone at Court. He didn’t let anyone else touch him; he never wanted them to. His hands went behind Mark’s head, feeling it bobbing. Mark’s tongue swirled around the head of Kieran’s cock, drawing another groan from his throat. His moan was echoed from the bed and his head whipped towards it.

Cristina’s hands were between her thighs, fingers dancing across her clit. Her eyes widened when she saw Kieran watching her, knowing she’d be caught. Kieran gently pushed Mark’s head away from him, as much as it pained him to do so.

“My Lady of Roses,” Kieran said as he moved toward her. “Do you remember what I ordered?”

“You told me to keep still, but, my King, I just couldn’t help myself watching you.” She was babbling, trying to escape punishment. Kieran propped himself over her.

“I know our Mark is quite beautiful with his lips wrapped around my cock, but that doesn’t mean you can disobey me.”

“I’m sorry, Kier—”

“Is that how you address me, Cristina?”

“My King, my love,” she corrected.

He nodded. “Better.” He ran a gentle fingertip between her breasts, all the way down the middle of her body, down her slit. She jerked, trying to press his finger into her.

“My darling, you’re so eager. I would not be one to deny you what you so desperately seek.” His mouth followed the trail of his finger.  It latched onto her inner thigh, nipping and sucking. There would be a bruise there tomorrow, a reminder of him when they left. Kieran laid a kiss upon her cunt, but no more. “Tell me what you want, Cristina.”

“I want you to kiss me there,” she said quietly. Her legs were shaking in anticipation.

He licked his lips and the girl before him moaned. “Be more specific, Cristina,” he laughed.

She turned bright red. He knew Cristina enjoyed this dynamic as much as he did but talking dirty was new to her. “I want you to kiss my cunt, King Kieran.”

“As you wish, Princess.” His hands shoved her legs apart, as far as they would go. Her cunt was glistening. “Did you come before? Don’t lie to me.”

She shook her head.

“Good. You can come all you want now,” he said. Denial was something they had toyed with, but he had something else in mind today. Kieran buried his face in between her legs, lapping at her clit. She was screaming, words in Spanish he couldn’t catch. It didn’t take long for her to come. Usually, that’s when he would stop, but not tonight. He looked up at her, his face still wet with her.

“You should have listened to me, my Lady.”

 He fucked her with his tongue, slipping into her pussy as far as he could. She was shaking around him. Her moans were louder, fast than before, more desperate. As far as he knew, she had never been subjected to multiple orgasms in rapid succession. The idea drove him crazy with lust. He went back to work on her clit, two long fingers slipping inside her. He didn’t stop until she came three more times.

“Thank you,” she moaned. He watched, mesmerized, as her pussy flexed in the wake of her orgasms. Her arm was draped across her eyes, her breathing heavy.

Kieran grinned wickedly at her exhaustion. He was not done with her yet. He looked at Mark, who had been lying next to them—watching them. “It’s your turn, love. She tastes wonderful.” Kieran watched as Mark’s cock hardened again from its half stiff state. The two switched places.

“Mark, no. Please, I can’t,” Cristina cried. Kieran winked at Mark, who continued. She knew what to say if she really wanted them to stop.

“I do as the King says, my Lady.” His face went between her thighs, and Kieran placed a hand on his cock. There was nothing more beautiful to him than Cristina crying out as Mark pleasured her, or vice versa. He watched as Mark’s tongue went to work where his had been, licking and sucking and fucking. Kieran wanted more than his hand; he wanted Mark; he wanted Cristina. He grabbed the lubricant they kept next to the bed and lathered his cock in it. Mark moaned as he lined it up with his entrance.

“Do you want me to fuck you, Mark?” he asked, leaning down to whisper in his ear.

“Yes,” Mark said, still deep in Cristina’s cunt. She was nearly delirious with pleasure.

Kieran lubricated Mark’s entrance. Slowly, he worked his way in. Mark groaned, redoubling his tongue’s efforts on Cristina’s pussy. It wasn’t long until Kieran was thrusting quick and hard into Mark, desperate to feel him wrapped around his cock. He had missed this warmth. Still, he kept a measured rhythm. He only stopped for a moment as they readjusted, Mark’s cock lining up with Cristina’s cunt. Her legs were up over Mark’s shoulders.

“I want her to beg for it,” he told Mark.

“You heard him,” Mark said to Cristina, cock poised to enter her.

She groaned. “Please, I need you to fuck me. I want to feel it when Kier thrusts into you. Please, Mark, _please_.”

“I don’t know, my love. Maybe it’s been too much for you,” Kieran teased.

“No! Fuck me, Mark.”

Her opening didn’t need the same ministrations as Mark’s had. Instead, Mark thrust hard into her, provoking a scream that could probably be heard back at the Court. She groaned their names, and Kieran continued fucking Mark. Every time he thrust into the boy in front of him, he thrust into Cristina. The three of them worked together, like nature worked to change the seasons. Faster and faster they moved together, each working for the others’ pleasure. Cristina came one more time, babbling and begging for mercy. As Mark came inside her, Kieran also burst, crying out their names. The three fell to the bed together.

Kieran lay in the middle and he wrapped his arms around both of them. “I love you both, so much. My Mark, my Lady of Roses.”

The two locked hands across Kieran. Tomorrow night, he would return to the Court, and they to New York. But right now they had each other. And right now was enough. It had to be.


End file.
